In cooperation with scientists at the National School of Medicine and Pharmacy in Bamako, Mali, the NIH has developed a Malaria Research and Training Center. The goals of the MRTC are two fold. The primary goal is to develop a center of research excellence in Africa where the work is planned, directed and executed by African scientists. A second goal is to provide a facility in a malaria endemic area where the results of laboratory studies at the NIH can be readily applied to studies of malaria in the field. Three main projects are currently under way: 1) As a prelude to the evaluation of strategies for malaria control based on the concept of replacement of vector populations with mosquitoes unable to transmit the malaria parasite, we are examining, in depth, the genetic and biologic structure of vector populations in a series of distinct ecological zones in Mali (West Africa). To facilitate these studies, we are using the tools of molecular genetics directed at microsatellite polymorphisms, restriction length polymorphisms (RFLPs), and ribosomal and mitochondrial DNA. 2) We are applying molecular probes developed at the NIH to the study of the genesis and spread of antimalaria drug resistance in Mali. 3) Site preparation preliminary to the testing of NIH-developed transmission-blocking vaccines are under way in Mali. Special emphasis is being placed on the relative infectivity of human gametocyte carrier population to mosquitoes.